The present invention relates to a braking apparatus for a door closer.
In a door closing operation controlled by such a door closer, it is desired that either the closing operation be completely done at a fixed speed, or rapidly in an initial stage through a predetermined initial portion of the closure angular range and then fully closed more slowly in the remainder of the range. The speed change is effected by an adjusting valve or the like.
Such a conventional door closer, however, cannot properly resist an external force such as wind pressure acting on the door during the door closing direction. In such a case, the door may be rapidly fully closed even in the remaining part of the angular range, thereby causing damage to the door or its attachments, or the door frame, or smashing someone's finger or hand. Hence, the conventional door closer involves substantial safety problems.